The invention relates generally to power-driven conveyors and more particularly to thermoplastic endless belts that are positively driven.
Low tension, direct drive conveyor belts are typically used in situations where hygiene and cleanliness are critically important. For example, in food processing plants such as those that process meat products for human consumption, low tension, direct drive belt conveyors are used to transport items. Sanitation is critically important and, therefore, the endless belts used in such conveyors are conventionally made of materials that can be hygienically cleaned, such as thermoplastics or stainless steel.
Low-tension, positively driven flat conveyor belts are especially useful in conveying food products. One such conveyor belt is disclosed in U.S. Pat. No. 7,210,573. That belt has on its underside a plurality of equally spaced, parallel teeth extending across the width of the belt perpendicular to the direction of belt travel. Sprockets engage the teeth to drive the belt. But, unless the belt is restrained laterally in some way, it can wander to one side or the other and jam or damage its outside edge. Physical restraints or guides can help keep the belt on track, but do so by means of friction, which increases the amount of power and the size of the motor required to drive the belt.
Often, conveyor belts are retrofitted into existing conveyor frames. A conveyor frame having horizontal structural members generally causes vibrations when used with a thermoplastic conveyor belt such as that disclosed in U.S. Pat. No. 7,210,573.